The code for the clock is pretty much done. I made it really simple to communicate with all the different nixie tubes. You simply call the function bool Nixies::initialize(unsigned int theSerialPin, unsigned int theSerialClockPin, unsigned int theRegisterClockPin, unsigned int theNixieCount) on the nixies object with all the correct data and then you are able to talk to the nixies with it’s simple interface, as an example here is the code to display the time: